/*
 * Copyright (C) 2013 Brett Wooldridge
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.zaxxer.hikari.pool;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * This is the proxy class for java.sql.Statement.
 *
 * @author Brett Wooldridge
 */
public abstract class ProxyStatement implements Statement {
	protected final ProxyConnection connection;
	final Statement delegate;

	private boolean isClosed;
	private ResultSet proxyResultSet;

	ProxyStatement(ProxyConnection connection, Statement statement) {
		this.connection = connection;
		this.delegate = statement;
	}

	@SuppressWarnings("unused")
	final SQLException checkException(SQLException e) {
		return connection.checkException(e);
	}

	/** {@inheritDoc} */
	@Override
	public final String toString() {
		final String delegateToString = delegate.toString();
		return this.getClass().getSimpleName() + '@' + System.identityHashCode(this) + " wrapping " + delegateToString;
	}

	// **********************************************************************
	// Overridden java.sql.Statement Methods
	// **********************************************************************

	/** {@inheritDoc} */
	@Override
	public final void close() throws SQLException {
		synchronized (this) {
			if (isClosed) {
				return;
			}
			// HikariProxyPreparedStatement的isClosed改为true
			isClosed = true;
		}
		// 移出缓存
		connection.untrackStatement(delegate);

		try {
			// 关闭代理
			delegate.close();
		} catch (SQLException e) {
			throw connection.checkException(e);
		}
	}

	/** {@inheritDoc} */
	@Override
	public Connection getConnection() throws SQLException {
		return connection;
	}

	/** {@inheritDoc} */
	@Override
	public boolean execute(String sql) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.execute(sql);
	}

	/** {@inheritDoc} */
	@Override
	public boolean execute(String sql, int autoGeneratedKeys) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.execute(sql, autoGeneratedKeys);
	}

	/** {@inheritDoc} */
	@Override
	// **************执行方法****************
	public ResultSet executeQuery(String sql) throws SQLException {
		// 记录执行
		connection.markCommitStateDirty();
		// 调用方法
		ResultSet resultSet = delegate.executeQuery(sql);
		// 生成代理ResultSet
		return ProxyFactory.getProxyResultSet(connection, this, resultSet);
	}

	/** {@inheritDoc} */
	@Override
	public int executeUpdate(String sql) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeUpdate(sql);
	}

	/** {@inheritDoc} */
	@Override
	public int[] executeBatch() throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeBatch();
	}

	/** {@inheritDoc} */
	@Override
	public int executeUpdate(String sql, int autoGeneratedKeys) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeUpdate(sql, autoGeneratedKeys);
	}

	/** {@inheritDoc} */
	@Override
	public int executeUpdate(String sql, int[] columnIndexes) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeUpdate(sql, columnIndexes);
	}

	/** {@inheritDoc} */
	@Override
	public int executeUpdate(String sql, String[] columnNames) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeUpdate(sql, columnNames);
	}

	/** {@inheritDoc} */
	@Override
	public boolean execute(String sql, int[] columnIndexes) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.execute(sql, columnIndexes);
	}

	/** {@inheritDoc} */
	@Override
	public boolean execute(String sql, String[] columnNames) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.execute(sql, columnNames);
	}

	/** {@inheritDoc} */
	@Override
	public long[] executeLargeBatch() throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeLargeBatch();
	}

	/** {@inheritDoc} */
	@Override
	public long executeLargeUpdate(String sql) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeLargeUpdate(sql);
	}

	/** {@inheritDoc} */
	@Override
	public long executeLargeUpdate(String sql, int autoGeneratedKeys) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeLargeUpdate(sql, autoGeneratedKeys);
	}

	/** {@inheritDoc} */
	@Override
	public long executeLargeUpdate(String sql, int[] columnIndexes) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeLargeUpdate(sql, columnIndexes);
	}

	/** {@inheritDoc} */
	@Override
	public long executeLargeUpdate(String sql, String[] columnNames) throws SQLException {
		connection.markCommitStateDirty();
		return delegate.executeLargeUpdate(sql, columnNames);
	}

	/** {@inheritDoc} */
	@Override
	public ResultSet getResultSet() throws SQLException {
		final ResultSet resultSet = delegate.getResultSet();
		if (resultSet != null) {
			if (proxyResultSet == null || ((ProxyResultSet) proxyResultSet).delegate != resultSet) {
				proxyResultSet = ProxyFactory.getProxyResultSet(connection, this, resultSet);
			}
		} else {
			proxyResultSet = null;
		}
		return proxyResultSet;
	}

	/** {@inheritDoc} */
	@Override
	public ResultSet getGeneratedKeys() throws SQLException {
		ResultSet resultSet = delegate.getGeneratedKeys();
		if (resultSet != null) {
			if (proxyResultSet == null || ((ProxyResultSet) proxyResultSet).delegate != resultSet) {
				proxyResultSet = ProxyFactory.getProxyResultSet(connection, this, resultSet);
			}
		} else {
			proxyResultSet = null;
		}
		return proxyResultSet;
	}

	/** {@inheritDoc} */
	@Override
	@SuppressWarnings("unchecked")
	public final <T> T unwrap(Class<T> iface) throws SQLException {
		if (iface.isInstance(delegate)) {
			return (T) delegate;
		} else if (delegate != null) {
			return delegate.unwrap(iface);
		}

		throw new SQLException("Wrapped statement is not an instance of " + iface);
	}
}
